Device for controlling electrical circuits.



PATENTED JUNE 12, 1906.

E. O. SCHWEITZBR. DEVICE FOR CONTROLLING ELECTRICAL CIRCUITS.

APPLICATION FILED MAR. 26. 1904.

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Iv Gdmuml 0f UNITED STATES EDMUND O. SOHW A PATENT OFFICE.

EITZER, OF CHICAGO, ILLINOIS.

Specification of Letters Patent.

Patented June 12, 1906.

Application filed March 26, 1904. Serial No. 200.130.

To all whom, it may concern.-

Be it known that I, EDMUND O. SoHwEIT- ZER, a citizen of the UnitedStates, residing at Chicago, in the county of Cook and State ofIllinois, have invented a certain new and useful Improvement in Devicesfor Controlling Electrical Circuits, of which the following is a full,clear, concise, and exact description, reference being had to theaccompanying drawings, forming a part of this specification.

My invention relates to devices for opening or otherwise controllingelectrical circuits upon the passage. of unduly strong or overloadcurrents.

Prominent objects of the invention are to provide a simple, practical,and eifective device of this kind, to secure quick operation, to avoidharmful effects, to render unnecessary the introduction into the circuitof high .resistances, to permit accuracy of operation and control, tosecure simplicity and cheapness of construction, and to provide a formof device particularly ada ted for use in manhole-boxes of power andighting systems.

In the accompanying drawin s, Figure 1 is a front elevation of a deviceof t e class specified embodying my present invention. Figs. 2 and 3 arevertical sections of the same, taken on lines 2 2 in Fig. 1, with thedevice in unoperated and operated conditions, respective y. Fig. 4 is atop plan view of the deviclg, and Fig. 5 is a section taken on line 5 51n ig. 1.

The device shown in the drawings for carrfiing out my inventioncomprises a case 1 in t e orm of an inverted cup and a plug or closure2, which is ada ted to fit into the lower end of the case 1, t e caseand plug being conveniently screw-threaded to ermit .ready insertion andwithdrawal of the atter.

The case 1 can be of any suitable or desired cross-section, being shownwith a circular cross-section. It is constructed with a convex top and aconcave bottom, providing a lower wall or partition 3, having a centralopening or aperture 4. The plug 2 is also conveniently of circular formand is made hollow or chambered and provided with a top wall 5, havingan opening 6, which registers and corresponds with the o ening 4.

These two parts are desirably ma e of insulating materialsuch, forinstance, as ebon-. ts. A pair of metal plugs or rods 7 8 are inpositesides of such case, as shown in Fig. 2. The plugs 7 8 are of conductingmaterialsuch, for example, as brass or copper. The plug 2is providedwith a depending tube 9, of transparent material, such as glass, whichtube communicates with the interior or chamber of the plug 2. Adiaphragm10, consistmaterial, is interposed between ,the walls 3 and 5 of thecase 1 and plug 2, res ectively, and closes the passa e-way formed lEythe apertures 4 and 6. T e interior of the case 1 is normally filledwith mercury 11 or a similar fluid. An adjustable screw 12, Fig. 1,isinserted in the wall of the case 1 and arranged to be adjusted in andout, so as to, in effect, vary the size of the chambenof the case 1.

As a means of attaching the device and also making connection whenattached in positionas, for example, in a manholeboxa pair of metalclips 13 and 14 are secured to the case 1 by means of screws 15 15 and16 16, respectively. One of the screws 15 desirably passes into the plug8 and one ofthe screws 16 into the plug 7 ,whereby the 13 and 14 areprovided with slots 17 and 18, res ectively, whereb the device can beattac ed by means 0 screws or bolts. The plug or closure 2 is desirablyprovided with a ventor outlet 19 and also with a pair of terminals 2020, which are understood to be connected with some local circuit, as arelay or alarm circuit.

The operation of the device is as follows: When the device is secured inpositionas, for example, in a manhole-boxconnection is made by the clips13 and 14 with two terminals of the circuit, so that the current passesfrom said clips to the metallic plugs or contacts 7 and 8 and thencethrough the mercury 11. So long as the current remains normal thecurrent passes through the mercury and the device preserves its initialcondition. When, however, the current becomes abnormal to apredetermined extent or remains abnormal to a less extent for apredetermined time, the mercury 11 expands and causes the breakage ofthe dia hragm 4, whereupon the mercury is release and falls or flowsinto the plug 2 and the tube 9, thereserted through the walls of thecase on op- 'ing of a layer of prepared paper or similar' clips 13 and14 make connection with the I, two plugs 8 and 7, respectively. Theclips quantlty as to ofier a negli The presence of the mercury in theplug 2 causes connection to be made between the contactsZO 20 thereof,whereby the local relay or alarm circuit is closed to ring an alarm orotherwise call attention to the fact that the device has 0 erated. Thevent 19 permits the access 0 air to the interior of the device tofacilitate the descent of the mercury. Fromthe foregoing it will be seenthat the device is simple and practical and efiective, that it can bemade to operate with great ac curacy, and that the operation occurs as aresult of expansion and not-as a result of fusion, as is common incircuit breaking devices, wherefore operation occurswith but a slightincrease in heat. It will also be seen that no high resistance isintroduced into the circuit by the device, the mercury having a highconductivity and being present in such large 'ble resistance. It willalso be seen that the time limit of operation of the device can beeasily regulated by adjusting the screw 12 so as to, in effect, vary thesize of the chamber in the case 1, and thereby subject the mercury to agreater or less ressure.

T e device can be designed and constructed for different conditions-thatis, different sizes of current, diflerentigtime limits of operation,&c.by varying he size and sha e of the mercury-containifig' case, itbein o served that operation naturally depen s on the size ofthecbpductor, its conductivity, and its coefiiciefit of expansion.

It will be understood that changes and modifications can be made in thedevice without departing from the spirit ofmy invention.

.What I claim is- 1. A cut-out for electrical circuits, comprising amobile conductor, and a closed case confining said-conductor and havinga fracturable retaiherada ted to be fractured on the ex ansionof saidconductor by the 1passage 0 an u'ndulys'trong current throug it, saidcu.tout having provisions for including said conductor normally incircuit.

2. A thermal cut-out, comprising a closed case containing a liquidconductor, and having a fractura le retainer normally holding saidconductor confined insaid case,"-b ut ada ted to be fractured on theexpansion of sai conductor by tile-passage of an unduly strong current,said cut-out having provisions for including said conductor normally. inthe circuit.

3. A cut-out, comprising a case made of insulating material, andprovided with conducting contacts extending through its walls, a

body of mercury confined in'sa-id case, said case having an aperture,and a 'fracturable retainer normally closing said aperture and- .adaptedto fit into-the bottom adapted to be fractured by the expansion of themercury by the passage of an unduly strong current through it.

4. A cut-out device comprising a case having a structurally separatefracturable retaining-section, and having revisions for including aconductor within t e casein circuit.

5. A cut-out device, comprising -a case made of insulating material andprovided with conducting contacts extending through its walls, said casehaving an aperture, and a fracturable retainer normally closing saidaperture.

6. In a device of the classspecified, the combination with a case rreceptacle, of a body or mass of conducting liquid confined in said caseor receptacle and included'in the circuit, and a retainer for holdinsaid liquid in suspense, said retainer being adapted to be actuated soas to permit the li uid to fall by the,'expansion of the same on t epassage of an unduly strong current, substantially as described.

7. In a device of the class specified, the combination with a caseorreceptacle, of a body or mass of conducting liquid confined in said case.or receptacle and included in the circuit, a retainer for holding saidli uid in sus' ense, said retainer being adapte to be bro en orfractured to ermit the liquid to fall by the expansion of the liquid onbeing heated by the passage of an unduly strong current, substantiallyas described.

8. In a device of theclass specified, the

combination with a case or receptacle, of a hquid contained therein, aretainer for. hold-' ing the liquid in said case or rece tacle, wherebyon the expansion of the liqui by an unduly strong current, the li uidwill be released, and a second receptac e for receiving the liquid whenreleased, substantially as described- 9. In a device ofthe classspecified, the combination with a case or receptacle, of a ua'ntity ormass of conducting liquid con fined in said case, a diaphragm forholding said liquid in sus liquid is'expande by an unduly strongcurrent, the diaphragm will be broken or ruptured, and the liquidpermitted'to fall, and a second receptac 0 when so released,substantially as desc for receiving the e ense, whereby when the 10. Ina device of the class specified, the combination of a case, a body ormass of cona ducting liquid contained therein, terminals in said case,adapted to make contact with said liquid therein, ing providedwith anaperture, a dlaphra closing said aperture, and

of said case and having aperture be ow sai diaphragm, substantially asdescribed. f: f

11. In a device of the class specified; the combination of a ;case,

a --liquid contained the bottom of the casebee a chambered p rig :2 5its uplper wall provided with an therein, a diaphragm holding saidliquid normally in suspense, and a receptacle for the liquid whenreleased,- said receptacle being formed of transparent material,substantially as described.

12. A device of the class specified, comprising a case provided with apair of terminals and having its bottom provided with an aperture, abody or mass of liquid contained in said case, a diaphragm below saidaperture, a chambered plug fitted into the bottom of the case and havingan aperture below said diaphragm, and a transparent tube attached tosaid plug, substantially as described.

13. In a device of the class specified, the combination of a case, aconducting liquid contained in the case, the latter bein provided withterminals, a threaded evice passing through the wall of the case andmade adjustable to permit variation of the size of the chamber formed bythe case, a diaphragm holding the contents of the case normally therein,and a receptacle for receiving the contents of the case upon theirrelease, substantially as'described.

14. In a device of the class specified, the combination with a case orreceptacle provided with terminals, of a liquid conductor confinedtherein, means whereby the conductor can be released on the pasage of anunduly strong current, and a plug or closure associated with the case orreceptacle for receiving the liquid when released, said plug or closurebeing ro vided with a pair of terminals between w 'ch connection is madeby the liquid when in said plug or closure, substantially as described.

15'. In a device of the class specified, the

combination with a case or receptacle provided with terminals, of a 1iuid conductor confined therein, means wherefb tor can be released on thepassage of an unduly strong current, and a plug or closure associatedwith the case or receptacle for receiving the liquid when released, saidplug or closure being provided with a vent for communicating with theoutside air, substantially as described.

16. In a device of the class s ecified, the combination of a conductorinc uded in the circuit, means forinclosing or confining said conductor,said inclosing means bein provided with an independent relatively agileportion whereby when the conductor is expanded by the passage through itof an uny the conducduly stron current, it ruptures said fragileportion, su stantially as described.

17. In a device of the class specified, the combination with a mobileconductor included. in the circuit, of a case confining said conductor,said casing having an independent relatively fragile portion adapted tobe broken or ruptured on the expansion of the conductor by the passageof an unduly strong current through it, and said conductor beingarranged to be removed from circuit on the breakage of said relativelyfragile part so as to open the circuit, substantially as described. 18.In a device of the class specified, 'the combination with a conductorincluded in circuit, means for inclosing said conductor, a retainer forholding said conductor in said inclosing means, said retainer beingadapted to be removed on the expansion of the conductor by the passagethrough it of an unduly strong current, substantially as described.

19. In a device of the classspecified, acase for holding a conductorsaid case having an independent. relatively weak portion, and means forincluding a conductor withinthe case, in circuit, substantially asdescribed.

20. In a device of the class specified, a containing-case provided withterminals adapted to make connection with a conductor within the case,and a fracturable retainer for normally holdin the contents of the casetherein, substantial y as described.

21. In a device of the class specified, a case rovided with terminalsextending from the mterior to the exterior of the .walls of the case,said case also having an opening, and a fracturable device for closingsaid opening, substantially as described.

' 22. In a device of the class specified, a case provided with terminalsextending from the interior to the exterior of the walls of the case,said case alsohaving an opening, a fracturable device for closing saidopening, and a second case adapted to be fitted to the first-mentionedcase and having'an opening registering with the openin in saidfirst-mentioned case and normally c osed'by said fracturable device,substantially as described.

In witness whereof I hereunto subscribe my name this 23d day of March,A. "D. 1904.

EDMUND O. SCHWEITZER. Witnesses:

A. MILLER BELFIELD, I. C. LEE.

